Whatever the nature of the conspiracy against Commodus, it brought to office in his place a better man, Publius Helvius Pertinax, prefect of Rome and former governor of Britain; but only temporarily, as an ominous pattern of events unfolded such as had followed the death of Nero.
Pertinax, an old soldier was made emperor by favour of the praetorians and their prefect. He lost that favour because in a conscientious effort to rectify the mistakes of Commodus and the evils which had sprung up during his rule, he tried to tighten discipline instead of relaxing it.
He lasted for a mere three months, until the praetorians mutinied, broke into the palace, murdered Pertinax, paraded his head through the streets on a pike, and offered the imperial throne to the highest bidder.

Pertinax reign might have been a short one. But it formed an enormously important precedent. Pertinax is understood to be the first 'Soldier Emperor' or 'Praetorian Emperor'. They were raised to the throne by the provincial legions which they commanded and ruled only till ejected and killed by another soldier who seized the succession.

The winner of a bizarre auction held by the praetorian guard to establish the imperial succession was Didius Salvius Julianus, an elderly senator.
Rome might have needed to accept the dictate of the praetorian guard, but the provincial armies had a preference for a chief of their own selection.
The legions in Britain and on the Rhine chose Clodius Albinus, the army in Syria proclaimed Pescennius Niger, the troops on the Danube hailed Septimius Severus.
Rome was the necessary objective. Helpless it lay waiting to be conquered by its own legions.
Albinus was a sluggard, a glutton, commanding little respect among his men. Pescennius was popular in the east, but his army had least experience of fighting. Severus was a hard soldier at the head of hardened troops, - and, being in Pannonia, he was nearest Rome.
Neither Albinus nor Pescennius was ready to strike. Severus marched on Rome.
Emperor Julianus alternated between empty threats and desperate offers of compromise. Severus ignored both. As he drew near, the praetorians, inexperienced in war and realizing themselves totally inferior to the advancing troops, deserted to Severus who, in order to save himself trouble and time, had no trouble making promises which he had no intention of keeping.
As he reached Rome on 10 June AD 193, no resistance was offered.
Didius Julianus was stripped of his imperial office and put to death on the orders of the senate.

Having disbanded the imperial guard and replaced it with a force 50'000 strong, from men of his own legions, Severus set about coming to terms with his two rivals, Pescennius Niger in Syria and Clodius Albinus in Britain. This he finally did in a most conclusive fashion by defeating them in turn: Niger at Issus in AD 194, and Albinus at Lugdunum in Gaul in AD 197.
Severus did not understand himself as fully established till he had inspired wholesome fear in the minds of any potential rivals by dooming several senators to death. Much because the rude soldier was accepted with reluctance by a body which still looked upon itself as the supreme constitutional authority.

In the years immediately before his accession Severus had held command on the most dangerous of all the Roman assignments, the banks of the river Danube. There he had learnt that the empire's need was defence, not aggression. But so too, that the aggressive barbarians needed to be kept in healthy awe of the Roman power. Severus was not far from being a barbarian himself. Grim, hard, unscrupulous, he lacked any statesmanly qualities, and yet he was free from wanton cruelty or vindictiveness. In his own, crude ways Severus commanded the empire as he had once commanded his troops as a general.

The domestic administration he left to competent and worthy officials, spending his own time among the armies on one or another frontier.
It was probably in Severus' time that the prefect of Rome, whose function was primarily military, was invested also with the main jurisdiction in matters of criminal law in and within 100 miles of the city, and the commander of the imperial guard, a military office, with similar jurisdiction over the rest of Italy and the provinces. After the fall and execution in AD 205 of Fulvius Plautianus, who had performed the latter duty with rather too much authority, Severus appointed in his place a noted legal expert, Aemilius Papinianus (d. AD 212). Within the army itself, the top jobs went to those with the best qualifications, not necessarily those of the highest social rank. Severus improved the lot of the legionaries by increasing their basic rate of pay to match inflation (it had been static for a hundred years), and by recognizing permanent liaisons as legal marriages - up until then a legionary was not allowed to marry. It was probably Severus, too, who improved the status of the ordinary soldier by extending the civil practice to allow veterans to style themselves honestiores (men of privilege) as opposed to humiliores (men of humble rank). As the distinction between citizens and non-citizens became eroded, so this new form of class-discrimination developed, which included separate punishments for the same crime.
Whereas humiliores could be sentenced to hard labour in the mines, honestiores were merely banished for a short term. The most common form of punishment for a minor offence was flogging, from which honestioreswere immune. Severus' philosophy of rule, was to pay the army well and to take no notice of anyone else. By 'anyone else' he meant, of course, the senate.

A professional soldier, Severus favoured those with the greater military experience to maintain the empire's frontiers in the east in the face of the marauding Parthians, and spent the last two and a half years of his life in Britain fending off the menaces of the northern tribes.
By unremitting hard work Severus restored and increased the security and prestige of the empire, which had been reduced in the days of Commodus.
But the desire to found a dynasty led him at last to the very blunder into which Marcus Aurelius had been drawn, as he let the imperial succession fall into the hands of his unsuitable son Bassianus, better known as Caracalla.

Publius Septimius Getaborn on 7 March AD 189 at Rome. Consul AD 205. Became emperor in 4 February AD 211. Wife: none). Died at Rome, December AD 211.

Severus had two unruly sons, Caracalla (AD 188-217) and Geta (AD189-212), whom he had nominated to rule jointly after him. Caracalla (a nickname - it means a Gaulish greatcoat) resolved that aspect of the arrangement by murdering his brother, and kept faith with his father's advice by increasing the pay of the army by 50 per cent, thus initiating a financial crisis.
Some sources suggest that it was to get more taxes to repair this crisis that he granted full citizenship to all free men in the Roman empire. Wether or not that is so, it is to Caracalla in AD 212 that is attributed this final step in the process of universal enfranchisement which had begun in the third century BC.
Caracalla in one swoop did away with the surviving distinction between provincials and citizens.
Though, the murder of his brother, was only the beginning of a continuous display of savagery by a tyrant. On his travels through the eastern provinces this was only further confirmed as, for a today unknown insult to his dignity, Caracalla had thousands of the population massacred.
These things were endured because he bought the good will of the soldiery by relaxation of discipline and lavish donations and increase of pay, both at the expense of the civil population as well as of military efficiency. While attempting to extend the eastern front Caracalla was murdered in Mesopotamia in AD 217, by a band of discontented officers who preferred their own candidate, Macrinus, commander of the imperial guard since Caracalla had done away with Papinianus.
(Papinianus, after Caracalla had murdered his brother, was ordered to 'play down' the crime on his behalf in the senate and in public. He responded that it was easier to commit fratricide than to make excuses for it.)

Macrinus, whose guilt in the assassination of Caracalla was at first undetected, achieved elevation to the imperial throne, since there was no obvious rival. But he was no soldier, and lacked both the abilities and the character to maintain the position. Once a rival emerged his fate was sealed. Though Macrinus was accepted by the senate, he never actually got to Rome. He continued the eastern war, only to be defeated and killed the following year by detachments of his own troops in Syria, who supported a 14 year old supposed son, but actually a distant cousin, of Caracalla who was known as Elagabalus.

There were no descendants of Severus, but there were his sister-in-law Maesa and her daughters Soaemias and Mamaea.
These Syrian women were ambitious and Soaemias and Mamaea had sons, Bassianius and Alexander Severus.
The elder of the two boys had been made high priest of the Syrian sun god Elagabal at Emesa. To win over the soldiery, his mother and grandmother did not scruple to spread the story that Caracalla was his father.
The actual involvement of Macrinus in the death of Caracalla was becoming known and the soldiery suspected their new emperor sought to curtail their privileges they had enjoyed under Caracalla. Hence the troops had ample reason to rid themselves of their ruler, only there was an alternative. The existence of Elegabalus gave them just this alternative, however dubious his supposed dependency was.
The bulk of the troops in Syria were easily incited to rise in the name of Caracalla's son. Macrinus was overthrown in a battle outside Antioch and the young high priest to an exotic Syrian god became Augustus of the Roman empire.
The reign was a vast orgy of the most extravagant and monstrous luxury and unspeakable vices. The only redeeming feature in it was the comparative absence of sheer blood-lust. In Rome the obscene rites of Oriental deities superseded those of the western pantheon.
Even after making every allowance for the exaggeration of shocked moralists or the inventive capacity of political enemies, what remains is still a picture of a totally decadent, if not depraved emperor, totally alien to all things Roman.
Maesa no doubt very soon realized that her second grandson Alexander represented the only possibility of her continuing power.
Pains were made to make Alexander Severus personally popular with the soldiery, who were sickened at the depravities of Elagabalus.
As it became evident that a jealous Elagabalus sought the death of Alexander Severus, the praetorians were driven to invade the palace, slay Elagabalus and proclaim the Alexander Severus emperor.

That a 16 year old could take office as emperor of the Roman empire and rule for thirteen years with more than moderate success was due partly to the fact that he was a sensible, likeable lad who knew his limitations and was prepared to take advice, and partly to his mother, Julia Mammaea, who recognized who would give the soundest advice.
The historians are full of praises of the virtues of the young emperor, the restoration of tranquility, the revival of prosperity which had suffered grievously from the merciless and capricious taxation imposed to meet the extravagances of the two last reigns.
Probably the controlling spirit of government for some years was Mamaea, who exercised a supreme influence over the son, whom she trained and guided.
In the civil administration Alexander was guided by a selected council of state.
But the problem of effective control was rendered for him more difficult than it had been for the Antonines, through the failure of military discipline an the insubordination of the rank and file of the soldiery for which Caracalla was mainly responsible.
Alexander owed his throne, probably his life, to the praetorians who therefore deeply resented any attempts to curb their powers and privileges. The young emperor in person led Roman armies on one great campaign against the eastern power which now again bore the Persian instead of the Parthian name. Trajan at the beginning, and Cassius Avidius in the second half of the second century had struck heavy blows against the long formidable Arsacid power. Severus also had conducted a vigorous campaign against the Parthians. But now the Arsacids had been swept away by a Persian chief, the founder of the Sassanid dynasty, who assumed the old Persian name Ardashir (Artaxerxes) and was bent on nothing less than the recovery of the old Persian empire. He deliberately challenged Rome, telling its emperor to withdraw from Asia. Alexander took up the challenge.
The emperor returned from the campaign to report to the senate of great victories won against immense odds. It seem clear however that the honours on the whole rested with the Persians, despite suffering heavy defeats in battle, had not in fact lost any territory.
While it would appear that the personal prestige ofArdashir was enhanced, Alexander's failure to sufficiently impress a soldiery already disposed to mutiny was fatal.
Alexander had scarcely returned to Rome when he was summoned to the northern frontier to deal with the German hordes.
In AD 235 the soldiery mutinied and Alexander and his mother were both set upon and murdered at the fortress town of Mainz.

On receiving the alarming news of the death of the two Gordians the senators, who could hope for no mercy from Maximinus, elected two of their own number as joint emperors, Balbinus and Maximus. Though they were also forced by the angry city mob to further associate the new emperors with a very youthful Gordian III who became Caesar.
Maximinus Thrax though still had to be reckoned with. After some delay he was now moving down from the northern frontier upon Italy, and the armies which could be hastily gathered had little hope of defeating his experienced troops.
Maximinus, passing the Alps, found before him a denuded country, and a strongly defended fortress in Aquileia. He began to besiege it and his troops began to starve. With no food they became mutinous and murdered their chief.
The senatorial revolution was apparently complete. the joint emperors set about an honest attempt to place the government on an orderly basis and restore the discipline of the army, which very soon mutinied again, cut them to pieces and declared the thirteen year-old Gordian III sole emperor.

Though he was only 13 at his accession, Gordian III, with the help of a capable regent, enjoyed civil and military success until the regent Timesitheus died of an illness. Timesitheus' successor though Philippus was considerably less noble-minded and strove from the very beginning to undermine and eventually murder the emperor he was charged to protect.
Gordian III was murdered in Mesopotamia in AD 244 as a result of Philippus' plotting while collecting wild animals to take part in his triumphal procession in Rome for his victories in Persia.

Philippus Arabs' reign was remarkable mostly for several revolts against him. Had he achieved his position by treachery against Gordian III, whom he reported to the senate as having died of illness, he possessed little moral authority with which to command the loyalty of the troops.
Philippus initial action was to make peace with Persia, to allow him to head for Rome and secure his throne.
In AD 245 he led a campaign against the Carpi and Quadi who had crossed the Danube and after a two year struggle successful forced the barbarians to sue for peace.
This success no doubt improved his standing, allowing him enough popular support to try and create a dynasty by making his son, also named Philippus, co-Augustus.
Yet the question of his own leadership was far from settled among the military, not to mention his son's accession.
The first rebellion was that of a certain Sibannacus on the Rhine, shortly afterwards followed by Sponsianus on the Danube. These revolts were brief and easily dealt with.
And yet early in AD 248 some of the legions on the Danube nominated Pacatianus as emperor. In turn the trouble among the Romans only further encouraged the Goths who now crossed the Danube and wrought havoc in the northern provinces.
Worse still, in the east of the empire the legions now hailed a certain Iotapianus emperor.
So dire did the situation grow, Philippus became convinced the empire was falling apart and offered his resignation to the senate.

Though one senator, Decius, responded to the emperor's address to the senate that all was far from lost and that Philippus should remain in office. When his estimation that both challengers would no doubt soon fall victim to their own mutinous troops came true, it was Decius himself who at the end of AD 248 was dispatched to the Danube to restore order among the mutinous soldiers.

In a bizarre turn of events the Danubian troops, so impressed by their leader, proclaimed him emperor in AD 249. Decius protested he had no desire to be emperor, but Philippus gathered troops and moved north to destroy him.
Left with no choice but to fight the man who sought him dead, Decius led his troops south to meet him. In September or October of the AD 249 the two sides met at Verona.
Philippus was no great general and by that time suffered from poor health. He led his superior army into a crushing defeat. Both he and his son met their death in battle.

After Decius' victory over Philippus Arabs at Verona, the senate made haste to confirm his election as emperor (AD 249).
Decius then still maintained, perhaps quite truthfully, to have accepted the decision of his soldiers to make him emperor against his will.
He would seem to have been a man of ability and character who was genuinely resolved to make worthy use of the power which had been thrust on him.
He proposed to restore the state by a revival of the old Roman virtues. The first steps to that end were to appoint an honoured and distinguished senator, Valerian, to the long obsolete office of censor, and a zealous return to the pristine worship of the ancient gods of Rome.
In turn this brought about a sharp but short persecution of the Christians, who had been undisturbed since the days of Marcus Aurelius.
But action of another kind was immediately necessary. The menace on the middle and lower Danube was greater than it had ever been before.
In AD 250 Decius was summoned to the Balkans by the news that a vast Gothic horde, supplemented by fighting men of various non-Gothic tribes, had swarmed over the Danube and was ravaging the Roman province of Moesia.
He found them engaged in besieging the fortress of Nicopolis, On his approach they broke off their siege and instead went on to attack the much more important stronghold of Philippopolis. Decius pursued them, the Goths then suddenly turned, surprised his army and defeated it, thereafter continuing onward to Philippopolis which fell after stubborn resistance.
Decius however reorganized his army, blocked the passes, cut off the Goths' way out of the Balkans and threatened them with destruction.
He was determined to deal them nothing less than an annihilating blow and at last he very nearly succeeded.
Both sides knew that the stake was all or nothing. In the great battle of Forum Trebonii, the emperor's son was slain before his eyes, but the first line of Goths was shattered, so too the second.
But the front of the third was covered by a bog in which the imperial legions, pushing on to complete the victory became hopelessly entangled, so that they were cut to pieces, emperor Decius perished with his soldiers (AD 251).

The disaster of Decius' defeat and death was terrific, but not without precedent. What was to follow however was even more ominous. Decius had realized that the Goths were foes who for the safety of the empire must be broken utterly and at all cost. Trebonianus Gallus, the successor chosen by his own soldiers was of a different mould than Decius.
Most likely to be able to return to Rome and secure his throne Gallus made a very unpopular peace with the Goths, allowing them to retire from Roman territory with all their booty and prisoners, and promising to pay them an annual subsidy.
Had Gallus won a peace which lost him the respect of many of his soldiers, then it wasn't long before the Goths broke it anyhow. Within only a few months the Goths and their allies were pouring into Illyria. Aemilianus, the commander of Lower Moesia, flung himself upon them and utterly defeated them. Having so redeemed Roman honour in the eyes of his troops and many other Romans, he then claimed the imperial throne for himself.
Leading his forces into Italy he took Trebonianus Gallus completely by surprise. The few troops Gallus could muster were utterly inferior in both numbers and quality to the hardened Danubian troops of Aemilian.
And so Gallus' desperate troops killed their own emperor at Interamna in order to escape slaughter (AD 253).

The senate had barely time to confirm Aemilian as the new emperor, before he was in turn overthrown a few months after his victory.
Valerian, nominated three years earlier to the office of censor by Decius, had been sent to command the armies on the Rhine. Gallus had called for him to come to his aid, when Aemilian's troops arrived, and yet the call had come too late.
Valerian had started out for Italy, but his emperor was dead before he arrived. But Valerian, once roused, did nor turn his troops around, but far more marched on, determined to overthrow the usurper.
Aemilian started out from Rome and moved north with his troops, to face off the invader. But history repeated itself, and Aemilian was slain at Spoletium by his own troops in order to avoid a fight (AD 253).

At teh death of Aemilian, Valerian assumed the throne, beginning a seven year reign which brought fresh disaster. With himself he associated his son Gallienus. The guardianship of teh German frontiers was placed in the hands of his son and colleague, together with the able soldier Postumus, who achieved several victories over the Franks and Alemanni. While Gallienus was engaged in teh west Valerian plunged into disaster in the east. Persian aggression was still a huge threat to the empire under its leader Sapor (Shapur). Sapor turned his arms on Armenia, aving first taken the precaution of having the Armenian king Chosroes assassinated. Armenia fell an easy prey to Sapor, who captured the Roman fortresses of Carrhae and Nisibis. Valerian marched his troops toward Edessa in Meopotamia to relieve the siege of the city, but suffered heavy losses. Seeking to come to terms with Sapor he was asked to attend a personal meeting with the Persian king, who at this encounter simply had him taken prisoner and taken to Persia, where he died in captivity. Valerian's army was trapped and forced to surrender.